Overview
- University of Adelaide researchers using a 3D clinostat found human, mouse, and pig sperm lost directional navigation in near-weightless conditions, with reported drops ranging from about 30% fewer cells reaching targets to fewer than 20% arriving versus roughly half in normal gravity.
- Fertilization still occurred under the simulation but was less efficient in animal models, including about a 30% reduction in mice after short exposure, while sperm speed and swim strength stayed largely unchanged.
- Short exposures during fertilization altered early embryo metrics in pigs and mice, and a 24‑hour exposure after fertilization slowed mouse embryo development and reduced blastocyst cell counts.
- High concentrations of progesterone, a hormone released near the egg, partly restored human sperm orientation in the simulator, suggesting a possible way to compensate for the loss of gravity cues.
- The team emphasized that clinostat results need confirmation in true or graded microgravity and said they will test lunar, Martian, and artificial gravity to assess risks and potential countermeasures for reproduction beyond Earth.